1. Field of the Invention
The present invention relates to a communication apparatus for receiving a content signal, a communication apparatus for transmitting a content signal, a communication system for transmitting and receiving a content signal, and a method for the same.
2. Description of the Related Art
In recent years, along with the development of the Internet, computer, mobile communications, and other technologies, it has become possible for individual users to obtain a video signal, audio signal, or other variety of content signals upon request when and where needed.
In a conventional communication system using the Internet and mobile communications, a specific communication line established by using an ISDN (integrated services digital network), a cellular system using up and down channels, or another communication medium enabling two-way communication is used for transmitting a content request signal from a terminal of a user to a server and for transmitting a content signal in accordance with the content request signal from the server to the terminal which sent the content request signal.
As explained above, in a conventional communication system, a content signal is sent from a server to a terminal of a user under the condition that the server received a content request signal. Further, transmission of the content signal is performed by individually establishing a communication line (assigning a channel) between the server and the terminal which sent the content request signal.
In the above conventional communication system, however, since transmission of a content signal from the server to the terminal is performed by individually establishing a communication line between the terminal which sent the content signal and the server, it becomes difficult to assign communication lines to terminals of all users demanding communication in a time zone where, for example, many users communicate by using their terminals.
While one method would be to increase the number of communication lines, since the communication capacity of a communication medium as a whole is limited, when assigning communication lines to many users, there is a disadvantage that a communication capacity able to be assigned to one user becomes small and the communication time becomes long.
The present invention was made in consideration of the above disadvantages of the prior art and has as its object to provide a communication apparatus for receiving a content signal, a communication system for transmitting a content signal, and a communication system for receiving and transmitting a content signal capable of reducing the volume of communication via individually established communication lines between a server and terminals and a method for the same.